Control system for clothes dryers



Jan. 20, 1959 FIG.|

M. F. MET

ZGER

CONTROL SYSTEM FOR CLOTHES DRYERS Filed Jan. 16, 1958 4 Sheets-Sheet 1INVENTOR. MATT F. METZ GE R BY M My Hi5 ATTORNEY Jan. 20,- 1959 M. F.METZGER CONTROL SYSTEM FOR CLOTHES DRYERS' Filed Jan. 16, 1958- 4Sheets-Sheet 2 FIG.3

M 7 w 5 5 W n "a 8 4 4 9 5 4 3 5 6 3 9 2 5 3 2 l 5 8 3 3 z a 4 0 5... 24 MI 0 3 4 Z 4 4 5...: in v n V; v 5 4 4 4 INVENTOR. MATT F'- METZGERHIS ATTORNEY Jan. 20, 1959 M. F. METZGER 2,869,247

CONTROL SYSTEM FOR CLOTHES DRYERS Filed Jan. 16, 1958 4 Sheets-Sheet 3 rr E-EE$" K :f II H 2| l8 frt'z 35 g F c G s 0 o o O ,4 1, 'J '3 G "J O O46 22 u 0 0 0 ,-l7 3 w v A: "-30 1 0 52 O I l 23 f o o l \29 FIG, *4

INVENTOR.

MATT F. METZGIR HIS ATTORNEY Jan. 20, 1959 E R 2,869,247

CONTROL SYSTEM FOR CLOTHES DRYERS 76 FIGS F I G. 6

o FILL t 2 1 OFF WASH lamss] I RINSE 1 I conocusra HOT as com: 68 LARGEuncrzn SPIN 67 PUMP 66 wAsl-l 7| DRY 72 TIMER 64 DAMP DRY SMALL M50111:

4 8 l2. 16 2O 24 28 32 36 4O 44 INVENTOR. MATT F'- mc'rzszn H [5ATTQRNEZY United States Patent CONTROL SYSTEM FOR CLOTHES DRYERS Matt E.Metzg'er, Jeh'ersonville, Ind}, assignor to General Electrie'Conipany, acorporation of New York Application January 16; 1958; SerialNo. 709,296

4 Claims;- (Cl. 34-45 This invention relates to control systems forautomatically controlling clothes dry'ers during the drying operation,and more particularly it relates to a control system which permitsSelection of a damp drying cycle as well as a regular drying cycle. Theinvention has general application to clothes dryers but is particularlyuseful in combination clothes washing and drying, machines.

In the co pending' application Serial No. 584,658 of John W. Tome; andTohn E. Ryan, filed May 14, 1956, now Patent No. 2,819,540, and assignedto General Electric Company, owner of the present application there isdescribed and claimed an improved control system for combinationwasher-dryers which in turn represents an improvement on co-pendingapplication Serial" Number 512612 of Water Gray, Jr., filed June 2,1955, and also assigned to General Electric Company. The washerdryers ofthese aforementioned applications are of the typeprovided with heatingmeans and timing means which cooperate with each other to insure properdrying of the clothes. The aforementioned applications also eachdescribe a' cool-down period provided subsequent to operation of theheating means. In each case the clothes are completely dried at the endof the operation, with the drying being provided to the exact properextent by use of the combination of thermostatic and timingarrangements.

However, there are many clothes which require ironing after they havebeen through a drying process; many of these clothes, inturn, requirepre-dampening for the ironing operation. Inotherwords, the housewife hasto undo some of the effect of the dryer by once again wetting theclothes. Since it is a relatively simple matter for the housewife tosegregate the clothes requiring such dampening into an individual load,it is a most desirable feature that the dryer permit the housewife toselect either a full and automatic drying sequence or a sequence Wherethe clothes arest'ill ina damp condition at the end of the cycle so thatthey are ready to be ironed. It is important to provide this additionalfeature in a simple easily controlled manner for the convenience of thehousewife, and at the same time to do so without requiring a majoradjustment or a major amount of expense in the commercially producedmachine described and claimed in the Toma et al. application.

The primary object of this invention is therefore the provision of a newand improved control for the drying operation of a laundry machine whichprovides selectively either a full automatic drying cycle or a damp drydrying cycle.

A further object of the invention is the provision of such a control, ina machine of the general type s'etforth in the aforementioned Toma etal. application, where the desired effect is obtained through theaddition of a minimum of equipment and with a minimum of modification ofthe Toma'et al. construction.

In carrying'out' the invention in one form thereof, there is providedclothes drying apparatus having clothes tumbling means for tumbling theclothes throughout the "ice 2. length of the drying' cycle until theapparatus is shut ofi. A control system is provided which includesthermostatic means responsive to the temperature within the apparatus;the thermostatic means are movable to a normal position in response todecreases in temperature and to a tripped position in response toincreases in temperature. sequence control mechanism includes a timerand switch cans operated by the timer so as to control the operations ofthe apparatus and of the timer itself; the switch means also operateappropriate means, such as an electric motor for instance, to actuatethe tumbling means. A first energizing circuit for the timer is providedand the thermostatic means, in its normal position, opens this firstcircuit so as to die-energize the timer; in its tripped position, thethermostatic means complete the first circuit so as to restart thetimer. The timer also controls operation of control means to control theheating means jointly with the thermostatic means so that the heatingmeans are energized when the thermostatic means are in their normalposition. After the last of a pre-determined number of trips of thethermostat the switch means deenergizes the heating means and energizesthe timer independently of the thermostatic means. This provides aperiod of tumbling without heat until the apparatus is ultimately shutoif by the timer.

The timer operated switch will close at the appropriate time for eachcycle, regardless of What final effect is desired by the housewife.Unless the manually operated switch is also closed the second timercircuit is not completed, and a full drying cycle is provided. If,however, the housewife has closed the manually operated switch, thecool-down tumbling period without heat will be started by the timerregardless of the position of the thermostatic means thereby eliminatingthe end of the operation of the heating means, and the housewife isprovided at the end of the cycle with damp clothes all prepared for asubsequent ironing without the necessity of re-we'tting them.

The subject matter which terms this invention is particularly pointedout and distinctly claimed in the concluding portion of thisspecification. The invention however, both as to organization and methodof operation together with further objects and advantages, may best beunderstood by reference to the following description when taken inconjunction with the accompanying drawings.

In the drawings, Fig. 1 is a front elevational View of a combinationwasher-dryer;

Fig. 2 is a fragmentary cross-sectional view taken along line 2-2 ofFig. 1;

Fig. 3 is a rear view of the machine with the rear panel removed toillustrate details;

Pig. 4 is a side elevational view of the machine partially in sectionand with certain surfaces broken away to' show details; and

Fig. 5 is a schematic electrical Wiring diagram, and Fig. 6 is asequence control cam chart illustrating a control system for the machinewhich embodies this invention in one form thereof.

Referring now to Fig. l, I have shown my invention in one form asapplied to a domestic laundry machine comprising a combination washerand dryer. The operating elements of the machine are included within anouter cabinet structure including a wrap-around central section 1. Thecentral section 1 is supported on a base and toeboard assembly 2 andcarries a separate top 3 provided with an integral backsplash panel 4Access to the interior of the machine is" provided by a door 5 mountedon concealed hinges and opened by means of a knee operated latch control6.

The machine is so constructed that when a load of soiled clothes isplaced therein, it proceeds through a sequence of operations, firstwashing the clothes and then drying them. In order to provide completeflexibility of operation of'the machine a number of operator controlsare included therein, these controls being mounted on the backsplashpanel 4. The controls includes a plurality of push-buttons consisting ofan off button 7, hot and warm water buttons 8, a damp dry switch 9, anda dryer control or omit dry button 10. A rotatable control knob 12 isprovided for convenient operator selection of any separate sequence ofoperations, and a second control knob 13 is included for operatorselection of operating temperatures for the drying portion of the cycleof operation. As shown in Fig. 4, the machine is of the horizontal axistype, that is, it has a clothes basket or drum 14 mounted for rotationon a generally horizontal axis within an outer enclosing tube structure15. The basket 14 comprises a cylindrical shell 16 which is closed atits rear end by means of a suitable wall or plate 17 and which alsoincludes a front wall 18 formed so as to define an access or loadingopening to the basket. The basket is rotatably supported by a shaft 19which is mounted in an elongated bearing 20 supported from the rear wall21 of the tub. The tub is provided with an opening 22 in the front wallthereof which is aligned with the access opening to the basket so thatclothes may be placed into or removed from the basket. The door 5 (seeFig. l) seals against a suitable gasket 22a (Fig. 4) to close thisopening during operation of the machine.

During machine operation basket 14 is driven by an electric motor 23through a drive including a pair of flexible belts 24 and 25 (Figs. 2and 3). The belt 24 connects the output pulley 26 of the motor 23 to theinput pulley 27 of a transmission assembly 28. The belt 25 connects theoutput pulley 29 of the transmission assembly 28 to a basket drivepulley 30 mounted on the shaft 19 of the clothes tumbling basket 14. Thetransmission assembly 28 is of the multiple speed type, that is, theratio thereof can be changed so that the basket is driven at twodifferent speeds. The transmission assembly thus provides one basketspeed for clothes tumbling for washing and another basket speed forcentrifugal liquid extraction. The ratio of the transmission assembly ischanged by any suitable means such as a spring-biased solenoid actuatedplunger 31. When the solenoid 32 controlling the plunger 31 isde-energized, the transmission ratio is such that the basket is drivenat a suitable speed for washing and tumbling clothes, for example,forty-four revolutions per minute. However, when solenoid 32 isenergized, the plunger 31 changes the ratio of the transmission so thatthe basket is driven at a suitable speed for centrifugal extraction, forexample, two hundred revolutions per minute. During the operation of themachine the basket 14 is continuously rotated by means of this drive.The preferred sequence of operations through which the machine proceedsto wash and dry the clothes contained therein is described hereinafter.

To heat the clothes during the drying portion of the cycle, and also towarm the wash water during the washing portion of the cycle whendesired, there is provided in the machine a heater assembly includingtwo heaters 35 and 36. These heaters are mounted within the upperportion of the tub 15 so that when energized they beat the basket 14.The heating elements are preferably of the sheathed type in which aresistance wire is maintained in spaced relation with an outer sheath bya highly compressed granulated heat conducting electrically insulatingcompound such as magnesium oxide. When the heaters are energized duringthe washing cycle, they heat the water by first heating the basket.Then, as the basket dips into the wash water at the bottom of the tub,it in turn heats the water. In other words, the rotating basket servesas effective heat transfer means between the heating elements and thewater or other washing liquids. When the heaters are energized duringthe drying cycle the heat transferred to the basket is then passed on tothe clothes to cause vapor migration out of the clothes. Since the outercylindrical shell of the basket is perforated some of the heat from theheating elements passes directly to the clothes by radiation.

In order that the machine will not be damaged by the heat produced byheaters 35 and 36 it is necessary that basket 14 be rotating wheneverthey are energized. If either of belts.24 or 25 should fail, the basket14 would stop rotating since it would then no longer be connected tomotor 23. Therefore safety means are provided within the machine wherebythe heaters 35 and 36 are deenergized whenever either of the belts fail.The safety means comprise a belt switch 37 which is actuated upon thefailure of either belt so as to dc-energize the heater relay 38(schematically shown in Fig. 5 and thereby open the heater circuit. Thebelt switch 37 is arranged on a pivotally mounted sled 39 which supportstransmission assembly 28. Upon the failure of either of the belts thesled 39 is moved by spring biasing means attached thereto and thismovement results in the operation of switch 37. The arrangement of sled39 and switch 37 is fully de scribed and claimed in Patent No.2,750,782, issued to Daniel L. Du Hammell, Jr., on June 19, 1956, andassigned to the General Electric Company.

The means whereby water is admitted to and discharged from the tub 15during operation of the machine is particularly shown in Fig. 3. Thewater supply means includes connections 40 and 41 through which hot andcold water is supplied to the machine. For the wash operation, a valvecontrolled by a solenoid 42 admits hot water to the machine and thevalve controlled by an opposed solenoid 43 admits cold water to themachine. The hot and cold water valves under the control of solenoids 42and 43 discharge from a common outlet conduit 44 through a suitable airgap into a funnel 45. Funnel 45 discharges into a line 46 which leadsinto the interior of the tub 15 through a suitable connection 47 (Fig.4). The air gap provided by funnel 45 makes it impossible for the waterto be siphoned from the machine to contaminate the incoming water supplyline. In the illustrated machine, a pressure actuated sensing device orwater level control 48 controls both solenoids 42 and 43 to maintain theproper water level in the machine during the washing operation. Thissensing device is connected to the interior of tub 15 by a suitable line49. 1

The illustrated machine is of the type which uses cold water during thedrying cycle for condensing the moisture extracted from the wet clothes.This condenser water is admitted to the machine through an additionalsolenoid actuated valve controlled by a solenoid 50 (Fig. 3) which isenergized during the drying operation so that the valve passes water ata slow rate sufiicient to condense the moisture extracted from theclothes. As shown, the condenser water valve discharges into line 46through a separate funnel 51 provided as before with an air gap ahead ofit to prevent supply line contamination. From the funnel the condenserwater flows through line 46 and connection 47 into the tub. Condenserwater flowing slowly into the tub is spread over the side of the tub byan inverted V-shaped bead 52 (Fig. 4) formed on the tub wall directlybelow connection 47. The condenser water being so spread out cools asubstantial portion of the area of the side wall whereby there isprovided a large cool surface for condensing the moisture extracted fromthe clothes.

The wash and rinse water used during the washing portion of theoperation and the condenser water and the moisture extracted from theclothes during the drying operation are discharged from the machinethrough a sump 53 (Fig. 3) mounted at the bottom of the tub andconnecting with a suitable discharge hose 54 which leads to a motordriven drain pump 55 to discharge to the household drain. The flowthrough the discharge line may, however, be controlled by any suitablemeans such as, for example, by a solenoid actuated drain valve.

Referring now to the schematic circuit diagram of Fig. 5 and theschematic sequenceillustration of Fig;- 6, there is shown therein acontrol system for the combination washer and. dryerwhichembodies theinvention" in one preferred form thereof. The control system includesathermostat 56 provided withqa sensing bulb 57 within tub 1-5 tow-hichitisconnected by means of a hydraulic line 58 (see also Fig. 3). Thesensing bulb 57 may, as shown, be positioned: in the gap between, theside wall of the tub andv theouter surface of the basket so as to sensea temperature of? the clothes within the basket; The temperature at thethermostat, bulb is higher than the clothing temperature but it risesandfalls in a similar manner totheclothing temperature so that it can-beused as a close indication thereof.

Thermostati5-6 ha'sganormjal: position and atrip position-.- Initsnormal position it closes a set of contacts 59 andopens asecondsetof:contacts 60 while in its tripped position it closes' contacts 60and'opens contacts 59. In other words, contacts 59 are' normally closed andcontacts 60 are normally open. The thermostat. trips so as to open thecontacts 59 and close-contacts. 60: at a piedeterminedhigh temperature:within: thetuband it resets at. a predeterminedlower temperature soas'to' open the contacts 69 and re-close contacts 59. Suitable biasingmeans (not shown) may be included within the thermostat. so as to allowsome operator selection of the trip and resetting temperatures. Thethermostat 56 is used in: this. control system for the .prime purposeofcontrol-' lingheaters and 36' duringzthe drying operation and forcontrolling the actual length of the operationitself.

A sequence control arrangement is provided which is utilized inconjunction with the thermostatduring the drying operation. andindependently during the washing operation; The basic operation of thesequence control arrangement is provided by means of a suitable timermotor 61 and it includes a series of switches 62 through 72 which areactuated in adesired sequence by appropriate switch operating meansdriven bythe timer, as indicated schematically by-Fig. 5 Seque'ncecontrols are'well known, and several types are commercially available;the representation of Figs; 5 and 6 is therefore purely schematiditbeing understoodthat each of theswit'c'hes 62 to 72 is operated bymea'nssuch as ca'rns'. In-th'e particularrepreseatatibn or Figs 5' and 6 it isto be understood that each of the switches 6272 schematically shown inFig; 5 is closed during the periods indicated by th'e'heavy black linesin Fig. 6.

For example; switch 70 is actuated toits closed position on thediagrarnfrom point 28- to point; A scale has been shown on the cam ch'arfi'ofFig: 6; but it wil1 be understood that the scale is not necessarilytimed but shows the length of the impulses given by advancing thecams'in the forward rotational direction. In" other words;

the chart of Fig; 6 may be re arded for" the purpo'ses of this"application to be a development of the peripheries of the respectiveswitch operating earns, theheavy lines' showing the cam rises. Further,it will be understood that the timer camsare preferably driven with animpulseor intermittent motion by means'of a. suitable mechanism(notshown) connected between them and the timer motor.- Thus, atswitchover points where the chart shows one switch opening and anotherclosing there is a quick make and break action so that'one switch isclosed simultaneously as the other is opened.

Further details with respect to the operation of the new and improvedcontrol system will become apparent by a review of a typical sequenceof" operation. Since the invention is" particularly directed to a' phaseof the control of the drying operation, the drying operation will beexplained first. It will be understood, however, that normally thedrying operation will be preceded by, and will renew automatically, thewashing operation. Referring to Fig'. 6, it will be seen that the dryingoperati'on begins at point 28 of'the scale and that at thatpoint theswitches 62, 64, 65, 66, 70' and 72 of the sequence control are closed.The remaining switches of the control are open. Energization of motor23' without energization of solenoid 32 provides the tumblingspeed-circuit. With this switch arrangement, both heating elements 35and 36,- drive motor 23, condenser water valve solenoid 50, the drainpump 55, and the timer motor 62 are all energized. The power forenergizing these elements is supplied from a three-wire power sourcecomprising power supply lines and 76 and a neutral line 77. Thisthree-wire source may, for example, comprise the conventional 230 voltdomestic supply having a voltage of 230 volts between supply lines 75and 76 and a voltage of 115 volts between each of the supply lines andneutral line 77.

It is to be understood that a complete description of every elementrequired in a circuit for connecting the various electrical componentsacross the supply line and the neutral line is omitted for the sake ofclarity; in fact, such a complete circuit is readily apparent to oneskilled in the art, and one, for instance, is shown and described in theaforementioned Toma et al. application. However, for the sake of notproviding unduly lengthy explanations irrelevant to this invention, itis believed that the general construction will be amply clear from theschematic illustration of the connections as shown in Fig. 5.

Returning now to the description of the circuit, the drive motor 23 isenergized across supply conductor 76 and neutral line 77 through switch72 to provide tumbling speed rotation of the basket. Included in thiscircuit is omit dry switch 10 which is manually opened when it isdesired that the operation of the machine cease at the end of thewashing cycle (to be described) and which is closed as shown when adrying cycle is desired. In addition to energization of the motor, bothheaters 35 and 36 are energized at the beginning of the drying: cycle soas to apply maximum heat tothe clothes as they are tumbled. In order toenergize the heaters, heater relay 38 is energized by a circuit betweenconductor 76 and neutral line 77 through switches 72, 10 and 65.Energization of relay 33 closes switch arms 79 and 80 on contacts 81 and82 respectively. This action connects both heaters 35 and 36 acrosslines 75 and 76 so that the heaters are energized across a 230 voltpotential. In the case of heater 35, this is eifected from line 75through switch blade 79, contact 81,.heater 35, contacts 59 bridged bythe thermostat 56, contact 82, and switch blade 80 toline 76. In thecase of heater 36, the circuit is essentially the same with the singleexception that heater 36 is connected in parallel with heater 35 throughthe medium of closed timer operated switch 62. Thus, both heaters areenergized together until such time as thermostat 56 trips and opens thecontacts 59. At that time both heating elements are de-energizedsimultaneously.

During heating, the moisture extracted from the clothes by the heatingelements 35 and 36 is being condensed by the water provided through theenergization of condenser water solenoid 50 as a result of the closingof switch 70 by the timer to complete the connection between lines 76and 77 of the condenser solenoid. The condenser water which enters thetub is spread out by the inverted V-bead 52 and flows down the side wallof the tub in a thin film or sheet so as to cool the side wall andcondense the moisture extracted from the clothes. Switch 66 is closed toenergize the drain pump 55 across line 76 and neutral conductor 77 so asto discharge condenser water and condensed moisture from the machine.

At the start of the drying operation, timer motor 61 has also beenenergized between line 76 and the conductor 77 through the closure ofswitch 64; the timer motor thus.

continues to run until switch 64 opens. It will be observed by referringto Fig. 6 that switch 64 remains closed only for a brief period afterthe washer-dryer proceeds into; the drying cycle. Specifically, itremains closed so as to. energize the timer motor long enough for thetimer motor- I to 'close'all the other switches necessary'for the dryingcycle as set forth above. Thereafter switch 64 is opened which causesthe timer motor to be de-energized and this in turn places the controlof the heating elements and of the machine itself under the action ofthermostat 56.

During the initial period it is generally desirable to have heatingelements 35 and 36 both energized as described so as to supply maximumwattage for heating the clothes. A satisfactory design has been found,for instance, to provide a total of 4,000 watts, with heater 35 beingapproximately 2800 watts and the other heater 36 being approximately1200 watts.

Both heaters remain energized, applying maximum heat to the clothes,until the machine heats up far enough to cause thermostat 56 to trip atwhich point, as is fully explained in the Toma et al. application,substantially all of the surface moisture has been removed from theclothes, with, however, an appreciable amount of moisture stillremaining in the fibres of the clothes. It has been found that in theillustrated machine a desirable trip temperature for the thermostat is230 with a normal load of clothes being dried, the trip point beingslightly higher if there is more moisture to be extracted from the fibresuch as for heavy fabrics like shag rugs and dungarees, and being lowerfor a load of delicate synthetic fabrics. When the thermostat 56 trips,contacts 59 are opened and contacts 60 are closed. The opening ofcontacts 59 breaks the heater circuit so that both heaters 35 and 36 arede-energized and the machine immediately starts to cool down. However,the closing of contacts 60 energizes timer motor 61 once more betweensupply line 76 and neutral conductor 77 through switch blade 80 andcontact 82. This is effected by the connection through conductors 83 and84 which connect one side of the timer motor to one of the contacts 60.The timer motor, energized through this circuit, begins to drive thesequence control mechanism. Shortly after it starts to operate, that is,about at point 33 on the scale of Fig. 6, the timer causes switch 64 ofthe sequence mechanism to close which locks the timer in and continuesit in operation even if the thermostat should reset immediatelythereafter. Also, after the timer starts to operate, it opens switch 62thereby breaking the circuit to the heating element 36 so that it cannotbe re-energized even when the heater circuit is reestablished throughthe thermostat. The timer now also closes switch 63. After this, thesequence control mechanism then continues to operate for a brief periodof time while the thermostat cools, and then switch 64 is once againopened to make completion of the timer circuit entirely dependent on theclosed position of thermostat contacts 60. The machine continues to cooldown due to the de-energization of the heating element. At apredetermined temperature below the trip temperature the machine coolsdown enough for the thermostat 56 to reset and return to its normalposition reclosing contacts 59 and opening contacts 60 therebycompleting the heater circuit once again and de-energizing the timermotor. However, with switch 62 opened by the timer only heating element35 is energized and not heating element 36. Thus, only 2800 watts ratherthan 4000 are now applied to the clothes for the evaporation of theremaining moisture contained within the fibres.

If switch 9 is in its open position, that is, a damp dry operation isnot desired, the closing of switch 63 by the timer has no effect uponthe operation sinceswitch 9 is directly in series with switch 63. Inthis case, the drying action now continues on heater 35 alone until thetrip point of thermostat 56 is reached once again. At this point (39 onthe chart), the clothes are substantially dry, this is, an amount ofmoisture equal to approximately of the dry weight of the clothes remainsin them so they are completely dry to the touch. .However, even if this5% of moisture should evaporate no damage can be done sincedisappearance of all moisture will cause the machine to heat up veryrapidly to the trip point and heater 35 will then be de-energized by theopening of contacts 59 before any substantial overheating can occur..

The tripping of thermostat 56 for the second time again opens contacts59 and closes contacts 60, thus de-energizing the heating element 35; asbefore, this re-energizes. the timer motor 61. The timer motor nowdrives thetimer mechanism toward the off position of the washer-- dryer.Also, shortly after the timer motor again goes intooperation, thesequence control switch 64 is closed so as to lock in the timer circuit,and switch 65 is opened to open the circuit to the heater relay 38 sothat switch arms 79 and 80 move out of contact with contacts 81 and 82respectively. Thus, resetting of the thermostat cannot close the heatercircuits.

The machine continues in operation with the heaters off and with thetimer motor running for a predetermined period (point 39 to point 44)which provides a cooldown period for the clothes to come down to asuitable temperature at the point marked off on the chart. The timermechanism then opens switch 72 which de-energizes all of the elements ofthe control including the timer motor, the drive motor, the drain pump,and the condenser water solenoid, thereby terminating the operation ofthe machine.

The foregoing, with the exception of the description of switches 9 and63, represents in essence a summary of the operation of the controldescribed and claimed in the above mentioned Toma et al. patentapplication. The present application proposes, for that type of circuit,to add simply and economically, a damp dry sequence as well as thecomplete drying sequence just described; this is effected by theaddition of switches 9 and 63 in series as described. One end of theadded circuit is connected to the line 84, between switch 64 and line83, while at its other end the new circuit is connected to point 86.When it is desired to provide the damp drying circuit, switch 9 isclosed so that contacts 87 in Fig. 5 are closed. When this is done, theoperation in the drying cycle is substantially the same as describedthrough the first heating operation requiring both heaters 35 and 36.However, with switch 9 closed, the closing of switch 63 insurescompletion of a circuit through timer motor 61 even after the timermotor opens switch 64 at point 37 on the cam chart and the thermostatthereafter trips back to its normal position. At this point, in anordinary drying cycle, the timer would stop operating.

In the normal drying sequence, the movement of thermostat 56 to bridgecontacts 59 and open contacts 60 stops the operation of the timer motor61. However, to the contrary, with switches 9 and 63 closed a circuit isstill completed to the timer motor as follows: line 76, switch arm 80,contacts 82, contacts 59, line 88, switch 63, switch 9, conductor 83,timer, motor 61 and conductor 77. With the timer motor continuing torun, only a relatively brief period of heating, if any, is provided fromheater 35 before the timer opens switch 65 to de-energize relay 38thereby opening switch arms 79 and 80 and deenergizing the heater. Thus,the continued operation of timer motor 61 as a result of the use ofswitches 9 and 63 provides a time limit on the amount of time ofoperation of heater 35 by itself and stops the energization of heater 35without regard to the last tripping of the thermostat 56, substantiallyprior to the point at which the thermostat would normally operate. Inthis manner, sufficient dampness is maintained in the clothes so thatthey are ready for ironing and may be removed from the machine andironed immediately without any interme, diate step of dampening beingnecessary.

To complete the description of the control system of Fig. 5, theoperation of the machine during the washing operation will now bebriefly explained. For this purpose, let it be assumed that the sequencecontrol is set in the space just preceding 0 on the scale of the camchart, that is, in the off position. To initiate the washing operationthe sequence control is now manually advanced to a position slightlybeyond 0. As a result, cam actuated switches 62, 66, 69 and 7 1 areclosed, with the other switches being open. The closure of-switch 71provides an energizing circuit for the main drive motor 23 across line76 through switch 71, switch 67, contact 73, motor 23 and conductor 77.Also, an automatic water fill control is simultaneously energizedthrough cam actuated switch 69. This causes hot water to be providedthrough conduit 46 into tub until such time as pressure sensitive switch48 opens the circuit to de-energize solenoid 43. It will be noted, thatif so desired, a manually operated switch 8 may be actuated to cause thecold water solenoid to be energized at the same time as the hot watersolenoid to provide warm water .until actuation of pressure sensitiveswitch 48.

The tumbling washing action continues through the proper period, asdetermined by the timer motor 61 through its associated switches, andthereafter at point 11 on the cam chart scale the wash period terminatesand wash water is discharged from the machine by the drain pump 55. Thisis achieved under the control of switch 66 which closes to energize thepump between lines .76 and 77. At the end of the drain period, switch 68closes to initiate the fill operation in the manner previously describedin connection with the wash fill. Operation of the solenoid is againdependent on pressure sensitive switch 48 so that the supply of water iscut ofi after the appropriate amount has been introduced into the tub.The first rinse then takes place, and the rinse water is then drainedfrom the machine by reclosing of switch 66 to re-energize the drain pump55. At the end of this second drain the appropriate supply solenoids areagain energized, and for the particular sequence illustrated, a warmrinse fill is provided by energization of both the hot and coldsolenoids The water then again enters the tub until actuation of thepressure responsive switch 48 and the last rinse then takes place. Atthe end of this rinse the pump 55 is again energized through the closingof switch 66, After the free water has drained out through the pump asbefore, a spin or extraction cycle is provided through timer motor 61closing switch 67 to energize solenoid 32 and provide a spin action aspreviously briefly described. At the end of the desired spin. action,switch 67 opens and the motor provides once again tumbling speed for thebasket. At this time switch 71 is opened by the timer and, if switch 10is also open, the entire operation ceases, with the clothes in a dampcondition as a resultof the. washing, rinsing, and extraction actions.

If, however, switch 10 is closed, then the closing of switch 72, whichoccurs slightly before the opening of switch 71, will serve the samepurpose as switch 71 serves and will continue to provide an electricpath for the completion of the circuits through the various operatingcomponents. At this point then there starts the drying sequence whichhas previously been described in substantial detail.

It will be seen from the foregoing that the invention provides, in acombination washer-dryer machine, an improved control for the dryerportion of the sequence whereby a damp dry may also be readily providedas well as a complete automatic drying operation. It will further beclear that while for clarity the washer portion of the cycle has beenbriefly and schematically described the invention resides in themodification to the drying sequence and is thus equally applicable toseparate clothes drying apparatus as well as to combinationwasher-dryers.

While in accordance with the patent statutes I have described what atpresent is considered to be the preferred embodiment of the invention,it will be apparent to those skilled in the art that various changes andmodifications may be made therein without departing from the inventionand I therefore aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Clothes drying apparatus for tumbling clothes throughout a dryingcycle comprising clothes tumbling means; electrical heating means; acontrolsystem comprising thermostatic means responsive to thetemperature within said apparatus, said thermostatic means being movableto a normal position in response to decreases in temperature and to atripped position in response to increases in temperature; a sequencecontrol mechanism including a timer and switch means operated by saidtimer for controlling the operations of said apparatus and said timer;

means operable by said switch means for operating said tumbling means; afirst energizing circuit for said timer; said thermostatic means in saidnormal position opening said first circuit to de-energize said timer andin said tripped position completing said first circuit to re-start saidtimer; control means operated by said timer for controlling said heatingmeans jointly with said thermostatic means to effect the energization ofsaid heating means when said thermostatic means are in said normalposition; said switch means operating to effect the de-energization ofsaid heating means upon the last of a pre-determined number of trips ofsaid thermostatic means and energizing said timer independently of theoperation of said thermostatic means thereby to provide a period oftumbling without heat and ultimately shutting off said apparatus; and asecond energizing circuit for said timer including one of said timeroperated switches and a manually operated switch in series relation andeach having a closed position and an open position; said thermostaticmeans, when in said normal position, enabling closing of said secondcircuit; said timer being arranged to close said second circuit timeroperated switch during its operation in response to the next to last ofsaid pre-determined number of trips of said thermostatic means wherebysaid timer, when said manually operated switch is closed, continuesoperation without regard to starting of the last heating operation andtherefore starts the unheated tumbling period prior to said lastthermostatic means trip.

2. Clothes drying apparatus for tumbling clothes throughout a dryingcycle comprising clothes tumbling means; electrical heating means; acontrol system comprising a thermostat responsive to the temperaturewithin said apparatus, said thermostat being movable to a normalposition in response to a decrease to a predetermined low temperatureand to a tripped position in response to an increase to a predeterminedhigh temperature; a sequence control mechanism including a timer andswitch means operated by said timer for controlling the operation ofsaid apparatus and said timer; electric motor means operable throughsaid switch means for operating said tumbling means; a first energizingcircuit for said timer; said thermostat in said normal position openingsaid first circuit to deenergize said timer and in said tripped positioncompleting said first circuit to re-start said timer; control meansoperated by said timer for controlling said heating means jointly withsaid thermostat to effect the energization of said heating means whensaid thermostat is in said normal position; said switch means operatingto effect the de-energization of said heating means upon the last of apredetermined number of trips and energizing said timer independently ofthe operation of said thermostat thereby to provide a period of tumblingWithout heat and ultimately shutting off said apparatus; and a secondenergizing circuit for said timer including one of said timer operatedswitches and a manually operated switch in series relation and eachhaving a closed position and an opened position; said thermostat, whenin said normal position, enabling closing of said second circuit; saidtimer being arranged to close said second circuit timer operated switchduring its operation in response to the next to last of saidpredetermined number of trips of said thermostat whereby said timer,when said manually operated switch is closed, continues operationwithout regard to starting of the last heating operation and thereforestarts the unheated tumbling period prior to said last thermostat trip.

ture; a sequence control mechanism including a timer and a plurality ofswitches operated by said timer for controlling the operations of saidapparatus and said timer; motor means operable through one of saidswitches for operating said tumbling means; a first energizing circuitfor said timer; said thermostat in said normal position opening saidfirst circuit to de-energize said timer and in said tripped positioncompleting said first circuit to restart said timer; control meansoperated by said timer for controlling said heating units jointly withsaid thermostat to enable the energization of said heating units whensaid thermostat is in said normal position; a second of said switchesbeing in series with one of said heating units, said timer opening saidsecond switch during its operation in response to the first trip of saidthermostat; a third of said switches operating to effect thede-energization of both said heating units upon operation of the timerin response to the second trip of said thermostat and a fourth of saidswitches operating to energize said timer independently of the operationof said thermostat thereby to provide a period of tumbling without heat,said timer then ultimately shutting off said apparatus; and a secondenergizing circuit for said timer including a fifth of said timeroperated switches and a manually operated switch in series relation andeach having a closed position and an opened position; said thermostat,when in said normal position, enabling closing of said second circuit;said timer being arranged to close said fifth switch during itsoperation in response to the first trip of said thermostat whereby saidtimer, when said manually operated switch is closed, continues operationwithout regard to starting of the last heating operation on said oneheating unit and therefore starts the unheated tumbling period withoutwaiting for said last thermostat trip.

4. Clothes drying apparatus for tumbling clothes throughout a dryingcycle comprising tumbling means; a pair of electrical heating elements;a control system comprising a thermostat responsive to the temperaturewithin said apparatus, said thermostat being movable to a normalposition in response to a decrease to a predetermined low temperatureand to a tripped position in response 12 to an increase to apredetermined high temperature, said thermostat having a first normallyclosed contact and a second normally open contact which is closed whensaid thermostat trips; a sequence control mechanism including a timerand a plurality of switches operated by said timer for controlling theoperations of said apparatus and said timer; motor means operablethrough one of said switches for operating said tumbling means; a firstenergizing circuit for said timer; said thermostat in said normalposition opening said first circuit to de-energize said timer and insaid tripped position completing said first circuit through saidnormally open contact to restart said timer; a heater relay forcontrolling energization of said heating elements having contacts and anoperating coil; a relay coil circuit including a second of said switcheswhereby said timer controls said heating elements jointly with saidthermostat to effect the energization of said heating elements when saidthermostat is in said normal position; the circuit to one of saidheating elements including a third of said timer operated switches; saidtimer opening said third switch to de-energize said one heating elementin response to operation of said timer after the first trip of saidthermostat; said timer operating said second switch to de-energize saidheater relay during its operation after the second trip of saidthermostat; a fourth of said switches completing a second circuit toenergize said timer independently of the operation of said thermostatthereby to provide a period of tumbling without heat, said timer thenultimately shutting off said apparatus; and a third energizing circuitfor said timer including a fifth of said timer operated switchesReferences Cited in the file of this patent UNITED STATES PATENTS2,654,961 Manecke Oct. 13, 1953 2,717,455 Harris et al Sept. 13, 19552,819,540 Toma et a1. Jan. 14, 1958

